It's a myth. Like a holy grail of income some people are still believing into. There are no shortcuts, and people who are making passive income are making it because they were early on something. Because they chose to pursue something before it become a thing. Then others try to find a key element from that, like yield farming or something, but they never work, because only reason someone made passive income in the first place was because they were just in the right place at the right time. And you can't copy being lucky. You can always just to create your own luck by being aware of everything that's new in here. Like few people did with NFTs before majority of people even grasped what they were, or had even heard of them.
Being early is one way, being rich is also another way. If you are a rich person then you can find a million ways to actually make some good returns, otherwise it is not going to be that easy to handle it, and will definitely cause a lot of trouble for a lot of people. Poor people trying to invest into things to have passive income will usually find things with high risk and high return promises and get scammed during the process instead.
We need to learn to control our emotions and just wanting this is not enough reason to do it, because if it's a fake thing then you will lose your money. In the end, we have something decent with bitcoin, if you really want profit and not have much money then just invest whatever you have into bitcoin and wait, it will go up. If you have a lot of money then you will find plenty of stuff to get passive income anyway, the best way is usually proof of stake, which ETH has, and gives 5% or so return yearly at the moment.
I have mixed opinions about the belief that controlling emotions being the key to riches. It's not even clear what people mean with that as some just seem to think it's suppressing emotions.
Imho it's more about the attitude of being interested, looking into things combined with circumstances and luck than emotion control. Emotions might as well be good source and motivation for acting fast when needed. There are lots of stories about people "aping in" without research because they felt like it and that has made people both rich and to lose money. You just have to find right thing at the right time.
Controlling emotions, (or understanding them while feeling them more like it) helps us in lots of situations, but that's not really a key to make anyone rich. People who say that it helps usually mean day trading and keeping your nerves not to sell. But from my experience decision of not to sell has been easier then selling. It's way harder to sell the tops or cut your losses when you are waiting for 1000x more.
And when you use lots of money to stake eth, you still need to remind your self that eth gives around 5% yearly in eth, not in dollars. That's the reason why it's considered risky investment.